Plated and Armored Dinosaurs

       Some of the plant-eating dinosaurs developed unusual structures, or plates, to help protect them against the terrible teeth and sharp claws of the meat-eaters.

A Palaeoscincus

       One of the most interesting of the plated dinosaurs was Stegosaurus, whose name means the "covered lizard." Stegosaurus (steg-o-SAWR-us) was more than twenty feet long and weighed around six or seven tons. His legs certainly look as if they didn't match very well. The hind ones were very long and straight, while the front ones were short and extended out from his body and then down. These legs probably made Stegosaurus very slow-moving and clumsy, and he may have swayed from side to side as he walked.

       Down his back was a double row of triangular bony plates, and the end of his tail was armed with four huge spikes. The largest plates, above his hind legs, were three feet high. These plates probably helped to protect him against ferocious Allosaurus. Stegosaurus may have swung his spike-tipped tail back and forth like a club to ward off attacks.

A Stegosaurus.

       Inside his long, narrow, flattened skull was a brain about the size of a walnut. Just think of that! A reptile the size of an elephant with a brain the size of a kitten's! The nerve cord running down his back became very large, about twenty times the size of his brain, just over his hind legs. This nerve center is mistakenly called a brain‚ in an often-quoted verse by a newspaper columnist, but this nerve center wasn't a true brain. It was a kind of message center to relay messages from the brain. Stegosaurus wasn't a smart animal; in fact he wasn't even a smart dinosaur!

Knight working on Stegosaurus in 1899. 
(model for painting above.)

       Ages later an armored dinosaur developed, and he was truly a reptilian "tank." Palaeoscincus was his name (pale-e-o-SKlNK-us). He looked much different from the other dinosaurs. His legs were short and his body was only a few inches off the ground. His flat back was covered with large bony plates and along each side, from head to tail, was a row of sharp spikes. His tail was a heavy club ending in a large knob of bone. What a good weapon that tail must have been! If Tyrannosaurus attacked, Palaeoscincus could have pulled his legs underneath him and started swinging his tail.

       Stegosaurus and Palaeoscincus did not live at the same time. Stegosaurus lived during the Jurassic period and Palaeoscincus during the Cretaceous period.